Yesterday, my Samsung Focus stopped working properly.
I plugged it to the wall for hours, the battery icon showed that it was plugged, but the battery level did not raise. If I unplugged the phone, an immediate message of “Battery critically low” appeared.
After reading some posts, I realized that the battery was in fact being charged, but the OS was not “reading” the battery level correctly.
In my case, as in many others, it was fixed by simply entering the Diagnostics mode of the Samsung Focus, to directly read the “actual” battery level. After that, everything is back to normality.
1.- To enter Diagnostics mode, open the phone keypad and enter: ##634#
2.- To access battery information (and others), type *#2*# in the next keypad that will appear.
And that´s all.